This invention relates to a helmet, and more particularly to a helmet with ventilation for controlling the formation of fog on a shield thereof, and for respiration of a person wearing the helmet.
Helmets are well known, and are commonly used to protect the head from impacts, debris, etc. during activities including but not limited to vehicle operation. Generally, helmets comprise a shell made of a suitably durable material with a cavity therein for the head.
It will be appreciated that a helmet that completely encloses the head provides the greatest possible protection. Thus, it is common to equip helmets with a transparent shield to cover the eyes, to protect them while still permitting clear vision. Likewise, it is common for helmets to cover the nose and mouth and chin area completely.
However, this configuration has a number of problems. For example, air exhaled by the wearer of the helmet is warm and humid. In a conventional fully enclosed helmet, moisture from the exhaled air has no place to escape, and thus tends to collect on the inner surfaces of the helmet. This is of special concern with respect to the shield, since even a relatively small amount of moisture condensation or xe2x80x9cfoggingxe2x80x9d on the inner surface of the shield can obscure the wearer""s vision significantly. This is a disadvantage in particular for helmets meant to be worn in cold environments, as fogging becomes more severe when the shield is chilled. In addition, the air inside the helmet rapidly becomes hot, humid, and stuffy, making the helmet uncomfortable to wear.
Two methods conventionally are used to overcome these limitations. First, helmets have been equipped with air vents in order to permit the exchange of air with the outside. However, the airflow has proven to be less than satisfactory, and fogging of the shield remains a common problem. In addition, airflow generally has been inadequate to cool the helmet to the point where it may be worn comfortably for extended periods.
Second, it is known to eliminate the shield, leaving the area around the eyes open and unprotected. This certainly eliminates the fogging problem, but requires the wearing of a separate piece of eye protection such as a pair of goggles. It will be appreciated that this is a considerable inconvenience. Furthermore, even with goggles, such a helmet leaves a significant portion of the wearer""s face exposed. In high winds or cold temperatures, this can be uncomfortable. Indeed, in sufficiently hostile conditions, as those experienced by persons operating snowmobiles, there is a risk of injury due to excessive cold.
In addition to these difficulties, in a conventional fully enclosed helmet that incorporates a shield, it is not possible to include a visor. Shields are conventionally designed to be raised from a closed to an open position so as to permit conversation, adjustment of goggles, etc. If a visor is included with a conventional helmet, however, it blocks the movement of the shield to the open position. For this reason, known helmets may include either a shield or a visor, but not both.
Therefore it is the purpose of the present invention to overcome the deficiencies of the existing designs. It is the purpose of the present invention to provide a helmet that protects substantially the entire head while having sufficient ventilation both to control fogging of the shield and to provide sufficient air for respiration. It is a further purpose of the present invention to provide a helmet with sufficient ventilation to allow it to be worn comfortably for extended periods.
An embodiment of a helmet in accordance with the principles of the present invention comprises a shell that defines a cavity therein. The shell is adapted to enclose the head of a person wearing the helmet. The helmet includes a transparent shield engaged with the shell, the shield being moveable between open and closed positions.
The shell has at least one first air inlet and at least one first air outlet. The shell and the inner surface of the shield cooperate to define a first airflow path from the first air inlet, across the inner surface of the shield, and through the first air outlet. Thus, the inner surface of the shield is constantly in the path of air outside air moving through the helmet via the first airflow path. The outside air draws off moisture from the vicinity of the shield, minimizing moisture condensation or xe2x80x9cfogxe2x80x9d on the shield.
The shell also has at least one second air inlet and at least one second air outlet. The shell defines a second airflow path from the second air inlet to the second air outlet. The cavity of the helmet is in communication with the second airflow path via the second air inlet, so that exhaled air is carried away and does not accumulate within the helmet.
Another embodiment of a helmet in accordance with the principles of the present invention further comprises a separator. The separator is adapted to separate the first airflow path from the cavity.
Still another embodiment of a helmet in accordance with the principles of the present invention further comprises a visor engaged with the shield and moveable therewith.